10.11.2011 20:21

Bifferboard watchdog

For one of may projects I am using bifferboard. This is a quite small but mostly complete PC, designed and sold in UK.

It is not very powerful as it has only 32M of RAM and the CPU is 486 like 150MHz RDC R8610. What counts is the size of the board which is like a box of matches, but with ethernet and USB port. Also price is nice - 35pounds. Another nice thing is the biffboot bootloader, that makes a lot of things much easier - it enables you to flash the internal 8MB memory for kernel/system via ethernet and it has many other useful option for easy boot.

I am using debian on USB  with the bifferboard based on what famzah made. While there is already a lot of documentation and howtos for bifferboard in the wiki, it is not very comprehensive and sometimes lacking important things. There is a good mail conference however, where the author of the bifferboard is very active.

Because I need the system to run for a long time unattended, one thing I needed was a HW watchdog function.
Generally it is easy to enable watchdog if you know.. that its driver hard-sets time out to 5s. The simple driver rdc321x_wdt that was written by bifferos is really simple. It hard-codes the HW time out to that short time, but the default linux watchdog demon is refreshing the WD every 10s. Therefore almost immediately after you enable WD it resets the board.

What you need to do is

apt-get install watchdog




interval        = 3

Now both watchdog and wd_keepalive are working OK.

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